Night stress fast route to coronary

By ELEANOR BLACK

Working the night shift can not only ruin your social life, it puts you at a higher risk of developing heart disease.

A study published by the American Heart Association - and supported by several New Zealand cardiologists - finds the heart is forced to work harder to keep shift workers alert during the hours the body naturally prefers to rest and repair itself.

While there is no current research on the topic in New Zealand, cardiologists contacted by the Herald confirmed that shift work - and the sleep deprivation associated with it - pose a significant health risk.

"You know it's terrible for you. One of the well-known forms of torture is sleep deprivation," said Professor Hamid Ikram, head of cardiology at Christchurch Hospital.

Workers who alternated between day and night duty put their bodies through enormous stress, he said.

The body's internal clock dictated that blood pressure and heart rate should fall at night. But people who worked the late shift forced their blood pressure and heart rate up by trying to stay awake when the body most needed to slow down.

"Night shift isn't necessarily something that will cause you harm if you do it for a little while," Professor Ikram said.

"But if it goes on for months and years, it's a different story."

Researchers from the University of Milan who wrote the article published by the American Heart Association found that the production of cortisol, a hormone which stimulates the heart rate, did not adjust when people worked at night.

This meant they might not be able to handle stress as effectively as their colleagues who worked 9 to 5.

The scientists concluded that people did not adjust well to shift work, even after years of alternating schedules.

But Dr Drew Dawson, director of the Centre for Sleep Research at the University of South Australia, said shift workers probably suffered more heart disease because they drank too much coffee, ate fast food and did not exercise as much as they should.

"The Italian research is inconclusive. I'm not saying they're wrong, but there's not really good research to support it."

He believed that shift workers resorted to "inappropriate coping mechanisms."

"Night work forces you to choose between your sleep and your social life."

But Auckland road works supervisors Andrew McIntyre, aged 35, and James Kelly, 30, said they would not change their jobs for desk-bound day work.

At 9 pm they've got a long way until knockoff time at 4 am. But they do not always have to work nights, and neither would swap his routine for a strict 9-to-5 job.



Most of the road gang tried not to eat too much on a late shift because they knew it would probably be burgers or junk food.

"It turns your diet upside down, but we try to just have coffee and sandwiches," said Mr McIntyre.

Companies have recently put in a lot of effort to cut down the other, better-known effects of night shifts - grumpy, sleep-deprived and occasionally befuddled workers.

During the America's Cup, maritime police tried out a 10-day roster that ensured a maximum two nights in a row on night duty.

Night shifts alternated with two day and two evening shifts, followed by four days off. Generally, police officers work seven nights in a row as part of their five-week rotation.

"It was brilliant," said Sergeant Martin Paget, who developed the roster. "The guys loved it. They felt better and they weren't as grumpy."

After nearly 27 years of shift work, he would rather work any roster than the five-week model, which left officers short-tempered and so tired their judgments could be impaired.

"You only have to ask the wife of any policeman."